The precious stone traditionally given for a 40th wedding anniversary is the ruby. This vibrant red gem symbolizes love and passion, making it a fitting choice to celebrate four decades of marriage. Rubies are known for their durability and beauty, often considered one of the most valuable gemstones, alongside diamonds, sapphires, and emeralds. The richness of the ruby's color and its historical associations with royalty and nobility add to its allure as an anniversary gift. Couples celebrating their 40th anniversary often choose rubies not only for their aesthetic appeal but also for their deep emotional significance.